Boron‐Catalyzed C1 Copolymerization of Arsonium and Sulfoxonium Ylides toward Unrepresented Structures and Fluorescence Properties

Abstract The first synthesis of well‐defined poly(methylene‐ co ‐1,1‐diphenylpropenenylene) (C1‐ co ‐C1’), equivalent to poly(ethylene‐ co ‐diphenylbutadiene) copolymers was accomplished by C1 copolymerization of novel diphenylpropenyl triphenyl arsonium ylides (Ph 2 AY) and dimethylsulfoxonium methylide (Me 2 SY) using B‐thexylborepane as initiator. All polymerization conditions, including feed ratio, temperature, and reaction time, were optimized. A series of photoluminescent poly(ethylene‐ co ‐diphenylbutadiene)s were synthesized at different feed ratios, opening a new synthetic horizon for poly(ethylene‐ co ‐disubstitutedbutadiene) copolymers. Notably, a new C1 segment, arising from a double bond rearrangement, was confirmed by NMR, resulting in an unprecedented two‐monomer three‐structure random terpolymer. An unexpected red‐shift phenomenon in the fluorescence spectra was observed with increasing the ratio of Ph 2 AY in the copolymer. This shift is attributed to the aggregation of diphenylbutadiene segment, similar to through‐space conjugation (TSC), likely induced by a decrease in the crystallinity of copolymers. Furthermore, another disubstituted allylic triphenyl arsonium ylides, ( E )‐2‐phenylbutenyl triphenyl arsonium ylide (MePhAY) was also synthesized and investigated. These additional compounds expand the knowledge and the potential applications of such copolymerization techniques in advanced materials.